Phenol-Sulfate Conjugating Activity in Liver-Soluble Fraction of Fish

The phenol-sulfate conjugatin by the liver subcellular fractions from goldfish Carassius auratus, carp Cyprinus carpio, rainbow trout Salmo gairdneri, and Tilapia nilotica has been studied using [35S] K2SO4. The cell fractination of goldfish liver was examined by the determinatin of respective markers for nuclear, mitochondrial, lysosomal, microsomal, and soluble fractions. Among those subcellular fractions, only the soluble fractin displayed the conjugating activityl The maximum activity of the exzyme in teh soluble fraction was obtained in the presence of 20 μmol of both ATP and Mg2+ in 1.5 ml of medium, although the activity decreased with an excess of ATP and Mg2+. This conjugatin was inhibited by more than 0.1 μmol of Ca2+ in 1.5 ml of medium. The enzyme exhibited the conjugating activity in the pH range 7.5-9.5; the optimum value was at 8. In the temperature range 5-40°C, the maximum conjugation in goldfish, Tilapia, and carp occurred at 35°C, in rainbow trout it occurred at 30°C. The phenol-sulfate conjugating activities in goldfish, carp, rainbow trout, Tilapia and rat were approximately 340, 82, 66, 200 and 720 nmol/g-liver per h, respectively.